Multistage compressor



Feb. 11, 1930. I c, UI 1,746,394

MULTI STAGE COMPRESSOR Filed Nov. 5, 1927 Fig.1..

21 1a Fig.2. HM 20 ,20 15 10 A TTORNE'Y.

p of compression; t

l atentctl ammu- Application filed lllcvemlier 5, rear. llcrinl lilo.ttitLlZ't.

This invention relates to gas, air or vapor compressors and moreparticularly to those compressors used in refrigerating machines of whatis known as the compression type.

t? Une ot' the objects of the invention is toproduce an apparatus of amore constant volumetric eficiency designed tor handling of the gasescompressed in such manner that their volume increase, due tosuperheating lit upon entering the apparatus, is held to a minimum.

Another object is to have the gases pass through the machine in a flowor stage direction correspondin. with the direction of heat die coldestgas entering at the coldest part oil the apparatus, the intermediatetemperature gas heing confined to the intermediate temper'atured part oithe ap paratus, and the hottest gas-passing out at the hottest part ofthe apparatus, and by this means minimizing the heat or energy slip backfrom compressed high temperature gas to uncompressed low temperaturegas.

Another object is to reduce the cost oft a two stage compressor byutilizing the crank case or chamber for the inter-cooler space betweenstages.

Another object is to produce a higher pres sure on the stufing boxthanthe pressure in the low pressure side and a lower pressure on th;stufing box than on the high pressure s1 e.

Another object is to have the crank case oil chamber at a more eficientoil separating temperature for the purpose of more easily evaporatingany entrained refrigerating media that may pass into it.

Another object is to eliminate an open passage from the crank case toevaporator and thus prevent heat slipping back during the stop periodinto the low temperature side that has been already taken out.

Another object is to make a more compact and chea or construction.

With t e above mentioned and other objects in view, theinventionconsists in the novel construction and combination of partshereinafter described, illustrated in the accompanying drawin s andpointed out in the claims hereto appen ed; it being understood thatvarious changes in the term, proportion, size and minor details ofconstruction within the scope of the claims may he resorted to withoutdeparting from the spirit or sacrifici ng any of the advantages of theinvention.

To more fully comprehend the invention reference is directed to theaccompanying drawings, wherein- Fig. l is a view in vertical section ctone emhodiment ot the apparatus tor carrying out my invention. I

Fig; 2 is a similar view taken on section line 2-2 of Fig. l.

lln the drawings wherein like characters of reference designatecorresponding parts in the several views, 1 indicates a crank case provided in its side wall with an opening 2 closed by a removable plate 3.The plate 3 is provided with a shaft opening through which into thecrank case extends a crankshaft A, the inner end of which rotates in afixed bearing 5 on the inner face of the opposite side wall 6 ot thecrank case. A stug box 7 surrounds the shaft where it passes through theopening in the plate 3, and the adjustable take-up l precludes pressurein the crank case passing therefrom around the shaft.

The crank case mounts a block 8 formed with a pair of cylinders 9 and 10therein, disposed with their lower ends in communication with the crankcase, the cylinder 9 being of a bore larger than that of cylinder 10.

Within the respective cylinders reciprocate the pistons 11 and 12,connected throu h connecting rods 13 with the cams lton s alt A, thecams afi'ording conventional crank throws.

The head or each piston is ported as at 15 and 16, and said ports arecontrolled re spectively by valves 17 and 18, illustrated in the form ofplates, the valve 17 closing the port 15 of the piston 11 on theunderside of the piston head, and valve 18 closing port 1.16 odiltpiston 12 on the upper side of the piston It will thus be observed thatthe valves of the respective pistons'operate in difierent directions.lhe cylinder 9 at a point slightly above the point of the lower end ofthe stroke of the piston therein is formed with an inlet port 19, andthe upper end of cylinder 10 is me ltti tlitl til contained in the crankcase and preferably maintained at the level indicated in the drawings,the lubricant bein supplied to the crank case through the filleropening, normally closed by a plug 23.-

With the shaft 4 rotating in the desired direction, the down stroke ofpiston 11 will create a vacuum in the cylinder 9 until the head of theiston uncovers port 19. During this operation, the downward movement ofthe piston, it being of greater displacement area than the piston in theadjoining cylinder, compresses the gases within the crank case. At thissame time the piston 12 is moving upwardly in the cylinder 10, and thegases contained within the cylinder above the piston are compressedtherein, seating valve 18, and on its pressure arriving at a pointapproximating that in the container, not shown, connected with theoutlet orifice 20, the valve 21 will be lifted and the gases dischargedthrough the orifice 20. On the next cycle of operation, that is theupward reciprocation of the piston 11 will compress the gases incylinder 9 above the inlet orifice 19 and its pressure will unseat valve17, en-

abling the gas to pass downwardly into the crank case. a

/ At this time iston 12 is moving downwardly, valve 21 eing held inclosed position by the pressure in the container, not shown, and valve18 is unseated, admitting thepassage of ases through ports 16, the gasespassin t rough the ports being under pressure, ue to the increaseddisplacement area of iston 11 over that of piston 12.

' t will thus be observed that the gases entering the compressor throughinlet 19 are compressed in successive sta es prior to passing throughthe orifices20, a so that the gases pass through the apparatus in acompression stage direction corresponding with the direction of heat ofcompression, the coldest gases being admitted into the cylinder 9; theintermediate temperature gases being contained in the crank case 1, andthe gases of highest temperature passing from the apparatus through thecylinder 10.

It will be observed that the valves in the premnt apparatus are ofsimple structure and positive operation; also that the liability of thegases of intermediate pressure containe withinthe crank case areprecluded from escaping therefrom around the shaft 4 by the stufling box7 4 It will be observed that the rotation of the member 22 in the formof a fan wheel, directs a current of air over means or elements 24,illustrated in the form of fins, associated with the crank case. Thisaction removes some of the heat of compression produced in the firststage of compression, and also, should the crank case receive entrainedrefrigerating media, raises the temperature of this media by directingair against the members 24:.

It will be observed that dependent on the temperature within the crankcase, the action of the air created by member 22 raises the temperaturewhen one condition exists, and lowers the temperature to that of thesurrounding air when another condition exists.

While the means 2 1 is illustrated in the form of fins, it is to beunderstood that any suitable construction for accomplishing the aboveresult may be employed.

When used in certain installations, it may be desirable to admit intothe crank case a gas of a pressure intermediate that in the cylinders 9-and 10. To accomplish this there is provided an inlet pipe 25 leadinginto the crank case and provided with a check valve 26 opening orunseating against the pressure in the crank case. This pipe 25 ispreferably connected with or leads from an evaporator, not shown, and avalve 27 therein serves to interrupt the gas flow therethrough. It willthus beapparent that when a supply of gas is available at apressurehigher than that compressed in the cylinder 9 and it is desiredto compress this gas to a higher pressure in cylinder 10, the same mayit down and without efiiciency loss delivered be, without stepping tothe crank case 1 through pipe 25 and raised to a higher compression incylinder 10.

I claim 1. A multiple-stage compressor comprising a pair of compressionelements, one of greater displacement than the other, a chamberintermediate the elements for receiving the compression from one elementand transferring it to the other and within which it is compressed bythe action of said compression elements, a controlled inlet port intothe element of greater displacement, a valve controlled'outlet leadingfrom the element of smaller displacement, and means for simultaneouslyoperating said compression elements in opposite directions.

2. A multiple-stage compressor comprising a crank case, a pair ofcylinders opening thereinto and one of a greater area than the other, apiston in each cylinder, one of a greater displacement than the other, aport in each piston, a valve cbntrolling the port in each piston, thevalve controlling the port in the pisd ton of greatest displacementopening into the crank case, the valve controlling the port in the otherpiston opening into its cylinder, a

valve controlled port leading from the latter/13o cylinder, and a gasinlet port communicating with the cylinder of greatest diameter.

3. A multiple-stage compressor comprising a plurality of compressionelements, certain of the elements being of greater displacement than theothers, a chamber intermediate certain of the elements for receiving thecompression from one element and transferring it to a succeeding elementand Within which chamber the compression is held by the action of saidcompression elements, a controlled inlet port leading into the elementof greater displacement, a valve controlled outlet port leading fromanother of the compression elements, and meansfor simultaneouslyoperating said compression elements in opposite directions.

4. A multiple-stage compressor comprising a plurality of compressionelements, certain of the elements being of greater displacement than theothers, a chamber intermediate certain of the elements for receiving thecompression from one element and transferring it to a succeedingelementand within which chamber thecompression is held by--t he action of saidcompression elements, a controlled inlet port leading into the elementof greater dis lacement, a valve controlled outlet port leading fromanother of the compression elements, means for simultaneously operatingsaid compression elements, means associated with the chamber forabsorbing the heat of the gases within the chamber, and means fordirecting an air current onto the walls of said means to maintain thetemperature thereof substantially corresponding with atmospherictemperature.

5. A multiple-stage compressor comprising a plurality of compressionelements, certain of the elements being of greater displacement than theothers, a chamber intermediate certainof the elements for receiving thecompression from one element and transferring it to a succeeding elementand within which chamber the compression is heldby the action of saidcompression elements, a controlled inlet port leading into the elementof greater displacement,'a valve controlled outlet port leading fromanother of the compression elements, means for simultaneously operatingsaidcompression elements, and means for admitting gas directly into thecompression chamber at a pressure between that generated by thecompression elements.

In testimony whereof I have signed my name to this specification.

. HERBERT C. GUILD.

